Environmental concerns and noise certification regulations have driven the significant reduction in jet engine noise in airplanes. As result, airframe noise has emerged has a leading component of aircraft noise during the final approach phase of a landing. One of the main contributors to this airframe noise in a landing configuration is the landing gear. In particular, on larger airplanes the landing gear is becoming the dominant source of noise. Landing gear systems have complex, non-streamlined geometries and generate highly turbulent wakes. Vortices shed from one component of the landing gear tend to impinge on other elements, thus generating noise. Furthermore, it is common practice to mount non-load bearing (non-structural) elements of the landing gear, such as hydraulic pipes, electric cables and locking springs, on the external surface of the load bearing structural elements, such as the telescopic struts and side stays. As a consequence the airflow over the landing gear is further disrupted. This is also exacerbated by the non-streamlined cross-section of some of the load bearing elements of the landing gear, such as the side-stays.
Initial efforts to reduce the noise generated by the landing gear when deployed have been focused on encompassing the existing landing gear structures in various streamlined fairings. Examples of this approach are disclosed in United States Patent Application US2009/0176078 and International Patent Application WO2004/089742. However, this approach adds weight and complexity, and hence cost, because the aerodynamic fairings are merely introduced in addition to the existing landing gear structures.